SYNTHESIS OF PEG-ENCAPSULATED SUPERPARAMAGNETIC COLLOIDAL NANOCRYSTALS CLUSTERS

PEG-encapsulated colloidal nanocrystal clusters (CNCs) have been synthesized via a one-step solvothermal process at a temperature of 230 degrees C. The composition, phase, and morphology of these CNCs have been characterized by X-ray diffraction and transmission electron microscopy. Studies show that each particle is a cluster structure consisting of small primary iron oxide nanocrystals. Magnetic measurements reveal the superparamagnetic nature of these CNCs at room temperature. The CNCs with different sizes (80 nm or 95 nm) can be obtained by changing the time of reaction. The dispersibility and colloidal stability of these CNCs with PEG as the major surface group have also been discussed. In vitro cytotoxicity of these CNCs with different thickness PEG layer on HeLa cell has also been assayed. Cytotoxicity results reveal that the CNCs concentration and the incubation time can influence the cell viability, and the size of CNCs almost does not affect the cell viability.